Chapter 26: The Male Reproductive System

Overview

• Main Functions:
  • Producing, storing, nourishing, and transporting gametes.
  • Gametes: Sperm in males, oocytes (eggs) in females.
  • Fertilization: Union of a sperm and an egg to form a zygote.

Key Components of the Reproductive System

• Gonads:
  • Primary reproductive organs (testes in males, ovaries in females).
  • Produce gametes and hormones that regulate reproductive functions.
• Reproductive Tract:
  • Series of tubes/ducts for receiving, storing, and transporting gametes.
  • Site of embryogenesis in females.
• Accessory Glands:
  • Secrete fluids that support gametes and facilitate fertilization.
• External Genitalia:
  • External reproductive structures.

Male Reproductive System Anatomy

• External Structure:
  • Scrotum:
    • Sack-like structure housing testes and epididymis.
    • Located outside the body cavity to maintain optimal temperature for sperm production.
    • Divided by the raphe into two scrotal chambers.
• Spermatic Cords:
  • Connect abdominal cavity to the testes.
  • Composed of fascia, connective tissue, muscle.
  • Enclose ductus deferens, blood vessels, and nerves.

Internal Anatomy of the Testes

• Testes Organization:
  • Divided into lobules by septa.
  • Seminiferous Tubules: Site of sperm production.
    • Lead into straight tubules and then into rete testis.
    • Connect to efferent ductules leading to epididymis.
• Cell Types:
  • Spermatogonia: Stem cells for sperm, undergo spermatogenesis.
  • Interstitial Cells (Leydig Cells): Produce testosterone.

Hormonal Regulation

• Testosterone:
  • Stimulates spermatogenesis, maturation of sperm.
  • Maintains accessory reproductive organs.
  • Develops secondary sex characteristics.
  • Influences growth, metabolism, and sexual drive.

Spermatogenesis

• Process Overview:
  • Starts with spermatogonia undergoing mitosis.
  • Forms primary spermatocytes, which undergo meiosis.
  • Resulting spermatids undergo spermiogenesis to become mature sperm.
  • Nurse Cells (Sertoli Cells):
    • Form blood-testis barrier.
    • Facilitate maturation of spermatids into sperm.

Anatomy of a Sperm Cell

• Structure:
  • Head: Contains chromosomes and acrosome.
  • Middle Piece: Packed with mitochondria for energy.
  • Tail: Flagellum for movement.

Pathway of Spermatozoa

• From Seminiferous Tubules:
  • Through straight tubules, rete testis, efferent ductules to epididymis.
  • Epididymis: Head, body, and tail regions; site for sperm maturation and storage.
  • Ductus Deferens: Transport sperm to ejaculatory duct.

Accessory Glands

• Seminal Glands (Vesicles):
  • Secrete seminal fluid rich in fructose and prostaglandins.
• Prostate Gland:
  • Produces prostatic fluid aiding sperm motility.
• Bulbo-urethral Glands (Cowper's Glands):
  • Secrete alkaline mucus to neutralize acidity and lubricate.

Composition of Semen

• Components:
  • Sperm cells, seminal fluid from glands.
  • Enzymes aiding sperm motility and passage.

External Anatomy: The Penis

• Regions:
  • Root, Body (Shaft), Glands Penis.
• Erectile Tissue:
  • Corpora Cavernosa: Paired structures.
  • Corpus Spongiosum: Surrounds urethra.
• Foreskin (Prepuce):
  • Contains glands secreting smegma.

Changes with Age

• Male Climacteric (Andropause):
  • Gradual decline in testosterone and sexual activity.
  • Occurs typically between ages 50-60.

Make sure to review these notes and rewatch the lecture video if necessary to ensure understanding. Feel free to reach out with any questions for clarification.